Furnace Monitoring and Tuning
Tuning is the careful reduction of excess air to the target range to improve efficiency during steady operation. Tuning is essentially monitoring and adjusting the stack O2 level.
Figure 1000-4 provides an overview of the monitoring and tuning step in the furnace tuning process. Figure 1000-3 shows a sample furnace performance chart.
Tuning During Process Changes or Upset Conditions
Under normal operating conditions, tune the furnace to the target O2 range. During process changes or upset conditions, increase O2 to allow room for:
• fuel rate adjustments
• possible instabilities and swing due to load change
The size of the increase must be determined by furnace history and experience. When the process change has been stabilized, tuning should be re-established to slowly return the O2 to target range.